A genetic component to the development of schizophrenia has been established, although markers for a genetic locus have not yet been identified in consistently replicated studies. Molecular genetic screening of large pedigrees, using restriction fragment length polymorphisms (RFLP's), have been successful, however, in finding markers linked to another neuropsychiatric disorder, Huntington's disease, and identifying other promising regions of the genome in Alzheimer's disease and manic-depressive disorder. A linkage to the proximal long arm of chromosome 5 in schizophrenia has also been reported, although it is not confirmed by other independent studies. Over the past 5 years, the present investigators have identified over 200 families in the United States and a catchment area of Northwest London, United Kingdom, with multiple ill members with schizophrenia. Thus far, approximately 100 of these families have had blood samples taken from available relatives and lymphoblastoid cell lines maintained in culture for continual DNA studies. The present proposal is for the extension of the collection of these pedigrees and for follow-up clinical evaluations for the application of molecular genetic techniques to the screening of these cell lines. Only funding for the clinical evaluations and maintenance of the cell collections is being requested in this application.